On 11/8/24 11:06, Mark L. Hammond via AMSAT-BB wrote:
A BIG negative---if you install the preamp, I don't see how to do full duplex, which we really should use on the birds. Some like Greencube didn't need full duplex. It's rare of course.
If you've got a 3D printer (or a friend who has one), put in a duplexer (2m/70cm) split, and use my 3-D printed version of AA2TX's 70cm Parasitic Lindenblad. It was published in the AMSAT Journal (Sep/Oct 2020).
The STL files needed for printing are here:
http://www.n0zgo.net/3d-lindenblad/
I have used it with great success on the RS-44 downlink, as well as an uplink antenna. I have a homebrew LNA in line with the antenna.
http://www.n0zgo.net/homebrew/70cm_lna/IMG_20201025_185513831.jpg
(I should write that latter one up -- someday)
73,
--- Zach N0ZGO